1. Field of the Invention
This invention relates generally to power transmission systems, more particularly monitoring and maintenance of power transmission systems, and specifically to monitoring of slip and the like of power transmission drives, such as belts, and other conditions, such as vibration in power transmission systems.
2. Description of the Prior Art
When a power transmission belt slip or skips the belt may overheat; the surface of the belt may become smooth and shiny, losing friction; bearings in the power transmission system may be shock loaded; the power transmission system loses efficiency; the belt may have a shorter life span; and/or system downtime may increase.
Traditionally the majority of industrial power transmission belt changes are carried out on a runtime or time interval basis. This is known as “Scheduled Preventative Maintenance.” Such planned maintenance and regular belt tension checks, direct slip measurement using contact measurement such as pulse generators or slip rings and/or non-contact optical or magnetic sensor based systems are typically used to ensure industrial or mobile power transmission belt condition and integrity.
Other prior attempts to monitor the condition of power transmission belts or the like have required special modifications to the belt. For example, Gartland, U.S. Pat. No. 6,715,602 teaches incorporation of at least one dedicated sensor containing an endless loop to be purposely embedded into a conveyor belt in order to facilitate the detection and location of a rip in a conveyor belt. As another example, two patents issued to Ahmed, U.S. Pat. Nos. 6,523,400 and 6,532,810, teach the use of a dedicated closed loop wire or strip which is required to be embedded in a belt to facilitate detection of a break in the closed loop. In both cases embedding such sensors is expensive and requires special production methods and additional materials which are extraordinary to the normal use of the belt.